Wnt protein is a secretory glycoprotein having a molecular weight of about 40,000 that is known to be an important intercellular signaling molecule for embryonic morphogenesis and hair follicle regeneration, and is involved in differentiation and functional maintenance of melanocytes. Nearly 20 types of vertebrate Wnt are known, these Wnt form subfamilies, and each binds to a seven-pass transmembrane receptor known as Frizzled and a single-pass transmembrane receptors known as LRP on the cell membrane. Wnt3a, which is a member of the Wnt family, has been clearly demonstrated on the basis of transplant studies in mice to maintain hair follicle formation induction activity of hair papilla by acting on hair papilla cells (Kishimoto, J. et al., Genes & Dev., 2000 May 15, 14(10), 1181-5), and considerable attention has recently been focused on its relationship with hair follicle induction. Research is being conducted on recombinant avian or mouse Wnt3a protein produced by avian Wnt3a or avian cells transformed with mouse Wnt3a gene by allowing this recombinant protein to act on mouse hair papilla cells.
When considering use in clinical studies applicable to humans, it is necessary to prepare large amounts of human Wnt3a recombinant protein instead of human or mouse protein. However, recombinant human Wnt3a has the problem of it being difficult to produce protein that retains adequate activity probably due to problems in translation and modification following transcription. Thus, selection of host cells for use in efficiently producing human Wnt3a recombinant protein that retains hair follicle induction activity is an important factor for elucidating the mechanisms of hair follicle formation and regeneration as well as screening and evaluating drugs that induce and accelerate hair follicle formation and regeneration.    Non-Patent Document 1: Genes & Dev., 2000 May 15, 14(10), 1181-5